Distribution Characteristics of Effective Source Rocks and Their Control on Hydrocarbon Accumulation: A Case Study from the Dongying Sag, Eastern China

The exploration conducted in the Bohai Bay basin, eastern China has demonstrated that the abundant petroleum resources have close affinities to the hydrocarbon kitchen with rich organic matter. A number of oil-generating associations with various characteristics of organic geochemistry and assemblages of multiple reservoir facies are developed due to the multi-center sedimentation, multi-source supply and multi-cycle evolution of filling, which have resulted in the formation of multiple oil and gas accumulation zones of various layers and trap styles. Among them the Paleogene Shahejie Formation is the most important hydrocarbon accumulation combination in the Dongying sag. Heretofore, its proved reserve has reached nearly 1.8×109t, which accounts for more than 90% of the total proved reserves of the Dongying sag. Based on previous studies, more than 600 source rock samples and 186 crude oil samples of the Shahejie Formation, collected from 30 oilfields, have been treated with organic geochemical testing     

Geoheritage at the small scale: tidal-zone bubble-sand structures as diagnostic paleo-environmental indicators,and their geoheritage significance

In identifying sites of geoheritage significance, commonly there has been an emphasis on the larger-scale features. However, the story of geology and the significant features that are critical to unravel geological processes and geological history are commonly small in scale. This contribution focuses on bubble sand and bubble-sand structures as features that are small-scale but nonetheless important to geology, and hence are of geoheritage significance. Bubble sand and bubble-sand structures are ubiquitous on modern beaches and tidal flats, occurring in the uppermost tidal zone of sandy beaches, as a distinct layer in a shoaling beach-to-dune stratigraphy, and are a diagnostic indicator of upper-tidal conditions where a rising tide and a concomitantly rising water-table interacts with the upper swash-zone wave processes. On sandy tidal flats, bubble sand and bubble-sand structures may occur in the mid- to upper-tidal zones; here they are also diagnostic indicators of tidal conditions, forming during a rising tide where a rising water-table forces air upwards to be trapped in moist sand. If found in ancient sequences, bubble-sand structures are a powerful environmental indicator of tidal conditions and, for beach sequences, an indicator of the high-tide level and sea level. Bubble-sand structures have been found in a number of ancient sequences throughout the geological record as far back as the Neoproterozoic, e.g. within beach-to-dune stratigraphy in Pleistocene limestones of the Perth Basin and in southeastern USA, and in tidal-flat sands of the Mesozoic Broome Sandstone of the Canning Basin. The bubble-sand structure is a significant geological tool for use in paleo-environmental and paleo-oceanographic reconstructions, and determination of the position of a paleo-water-table. Given the rarity of their preservation, these occurrences of bubble-sand structures are of geoheritage significance in their own right and, depending on age of sequence and how common they are in the region, they may be nationally significant or globally significant.     

松辽盆地德惠断陷火石岭组天然气成藏机理

火石岭组是德惠断陷深层天然气有利的勘探层位。在分析研究区构造演化史的基础上,对火石岭组典型的气藏进行精细解剖,结合地震、测井、钻井等基础资料,并综合轻烃、烃源岩、流体包裹体等分析测试数据,对德惠断陷深层火石岭组的天然气成藏机理进行了研究。结果表明,火石岭组烃源岩有机碳(TOC)平均含量大于1.0%,生烃潜力(S_1+S_2)的均值范围为0.5～2.0 mg/g,有机质类型多以Ⅱ_1～Ⅱ_2型为主,Ⅲ型为辅,有机质已达到成熟,成熟度(R_o)均值为1.5%,烃源岩具有较大的生烃潜力。火石岭组下部天然气来源于火石岭组烃源岩,而火石岭组上部天然气以火石岭组烃源岩生气为主,但受上覆沙河子组烃源岩混源影响。天然气运移以垂向断裂输导为主,层内砂体横向输导为辅。基于流体包裹体分析,结合火石岭组气藏气源对比与烃源岩生排烃期,认为火石岭组天然气藏存在三期成藏:130 Ma左右,对应营城组沉积初期;115～105 Ma左右,对应泉头组沉积期;95～75 Ma左右,对应青山口组—嫩江组沉积期。     

含水量对高含冰量冻结砂土屈服面的影响

以往关于冻土屈服特性的研究很少考虑含水量的影响,但实际工程中经常遇到的是变含水量情况,因此本文通过-5.0℃条件下高含冰量冻结砂土的一系列三轴压缩试验,系统地研究了含水量对屈服特性的影响,并且由此建立了带有含水量参数的偏应力-剪应变增量型关系式。试验结果表明：随含水量的变化,应力-应变曲线类型有明显变化,即在不同的含水量区间,含水量对硬化规律有不同的影响特性,因此为了使屈服函数的形式更加简单和提高拟合准确度,对于屈服函数的具体形式应该根据塑性剪应变（硬化参数）和含水量不同区间进行分别确定;当塑性剪应变较小时（0.00%~1.00%）,随含水量的增大,偏应力逐渐增加,而当塑性剪应变较大时（大于1.00%）,随含水量的增大,偏应力有一个先减小后增大的变化过程,并且42.0%可以作为含水量转折点;通过分段硬化原则建立的带有含水量参数的屈服函数与偏应力-剪应变的增量型关系式的模拟值与试验点基本相吻合,这说明得到的屈服函数与偏应力-剪应变的增量型关系式可以用于不同含水量条件下屈服面和偏应力-剪应变曲线的预测。     

马杏垣先生开合构造思想的提出、形成及最新进展

概述了马杏垣院士的学术生平与创建开合构造史实.开合构造提出是中国地球科学"百花齐放,百家争鸣"发展的结果;是黄汲清院士、张文佑院士、马杏垣院士领导的青年团队,在国际板块构造革命的新潮中,根据板块构造登陆存在的巨大问题,结合中国地质构造的特色,依据坚实的实际资料进行深入的全新探索.3位院士领导的团队又联合起来,进行开合构造的长期研究.2002年在构造地质专业委员会支持下,成立了开合构造研究组,召开了开合构造第一次学术研讨会,总结20多年研究成果,出了专刊书集.2015年研究组聚首北京,总结开合构造研究的新成果,并吸取地球物理研究新成果,准确地阐明开合构造的定义,提升了研究方法,总结了开合构造运动和开合构造体系特征,将构造动力来源初始点建立在古登堡面的开合构造转换带上,全新解析了转换带的重要作用,站在星球角度认识开合构造.最后,强调青年研究力量的培养,是开合构造走向世界的重要途径.     

藏南马扎拉金-锑矿床:成矿流体性质和成矿物质来源

马扎拉金-锑矿床是藏南巨型金-锑成矿带的重要组成部分,其矿床成因目前仍存在不同认识.通过主要矿石和蚀变围岩的岩相学、矿相学、流体包裹体和稳定同位素分析,探讨了马扎拉金-锑矿床的成矿流体性质、矿质迁移和沉淀机制.结果表明,马扎拉金-锑矿床成矿流体主要来自岩浆水,主成矿期流体为中温(约255℃)、低盐度(2.8%~3.5%NaCleqv)、富CO2流体,成矿压力约150 MPa,流体演化过程中的CO2与水的不混溶是造成矿质沉淀的主要原因,成矿金属主要来源于地层,特别是区域广泛分布的海相火山岩地层.     

中国新生代上地幔铅同位素地球化学场对成岩、成矿物质来源的制约——以斑岩铜矿床及铜镍硫化物矿床为例

区域成矿带铅稳定同位素地球化学研究是区域地球化学分区、示踪成岩成矿物质来源、阐明矿床成因的有效途径。本文以中国特有的大地构造背景为基础,以新生代上地幔铅同位素组成的地球化学场为依据,示踪了中国大型、超大型斑岩型铜矿床及铜镍硫化物型矿床的成岩成矿物质来源。结果显示:①斑岩型铜矿床及铜镍硫化物型矿床成矿母岩继承了所属陆块的上地幔铅同位素组成特征;②两类矿床的含矿岩体和矿石矿物铅同位素组成十分一致,示踪两者同源;壳熔花岗岩和围岩地层的铅同位素组成与矿石铅同位素组成迥异;③位于各陆块的斑岩型铜矿床及铜镍硫化物型矿床的成矿母岩和矿石铅同位素组成除继承了各陆块上地幔不同的铅同位素组成特征外,还示踪了壳幔层圈间耦合性的"块体效应",同时,上地幔铅同位素组成可能还具"延迟效应"。     

地下水源热泵水井泵砂与堵塞原因分析

地下水源热泵系统常会出现抽水井泵砂、抽水井和回灌井堵塞等问题,影响系统的正常运行或系统效率。以湖北省荆州市某地下水源热泵工程为例,分析了江汉平原广泛分布的卵砾石夹细砂含水层中成孔方法选择、滤料及过滤管设计中存在的问题;指出了目前在过滤管外包不锈钢丝网是防止在细砂层中水井泵砂的有效手段之一,但宜与泥浆密度轻、对地层污染小的反循环成孔工艺配合使用,且仍要根据含水层的颗粒级配曲线选择滤料,发挥滤料的过滤作用,避免过滤压力转移到包网过滤管,以减少抽水井堵塞。     

饱和土地下源u-P形式解答动力响应计算

一直以来,由Biot孔隙弹性动力方程得到的饱和土地下源Green函数都是u-w形式（u为固相介质位移,w为流相相对于固相的平均位移）。应用两相介质纵波解耦理论,得到了饱和土半空间地下点源荷载的u-P形式（P为孔压）Green函数频域解答;克服了u-w形式Green函数在边界元（BEM）积分时的增根影响。再由Hankel反演,结合Somigliana表象积分,完成BEM计算。并以计算结果分析了地下集中力作用时,饱和土位移、孔压、排水量等动力特性,这对地铁等交通工程、地震工程、土-结构动力相互作用（SSI）的响应计算都具有较重要应用价值。